Using a large longitudinal dataset including children who attended Head Start over two years, this study examined academic growth trajectories during the period between Head Start entry and kindergarten (2.5 years), and whether those growth trajectories differ by children's dual language learning status. Analyses comparing three groups of children (i.e., Spanish-English bilinguals, Spanish-English emergent bilinguals [EBs], and English monolinguals) showed three noteworthy findings. First, bilinguals entering Head Start with English proficiency showed similar developmental trajectories in vocabulary and math to those of monolinguals. Second, EBs entering Head Start with limited English proficiency presented the lowest baseline skills in vocabulary and math. Whereas the initial vocabulary gaps generally persisted over time, gaps in math between EBs and monolinguals narrowed by kindergarten. Third, no difference was found between bilinguals and EBs in their Spanish vocabulary development. Results highlight needs for additional instructional support and resources for EBs especially in their vocabulary development. (author abstract)